The state police had initially said the driver, who they did not identify, died in the 1:30 p.m. crash on the Mass. Pike westbound, but later, spokesman Trooper Todd Nolan said the driver had survived but sustained life-threatening injuries.

"The initial reports were that he was deceased and trapped," said Nolan. "Once they were able to extricate him, the responding Hopkinton EMTs worked on him and was able to get a pulse going."

The driver was taken to UMass-Memorial Medical Center in Worcester. His condition was not known at presstime.

The cause of the rollover is still being investigated, Nolan said. The truck had left the Mass. Pike and was on the on-ramp to Interstate 495 when it rolled over.

The on-ramp was closed from the Pike for more than two and a half hours. As of 5:45 p.m. Monday, only one lane from the Turnpike ramp to I-495 was open. The tractor-trailer had been moved to the median during rush hour, police said.

Nolan said it appears no other vehicle was involved in the crash.

Norman Miller can be reached at 508-626-3823 or nmiller@wickedlocal.com. For up-to-date crime news, follow Norman Miller on Twitter at @Norman_MillerMW.